1. Field of the Invention
This invention relates to ramming machines particularly those used in the production of Compressed Earth Block, Stabilized Compressed Earth Block, and other similar material units.
During the next 20 years, the world's human population is expected to double. Considering what is happening to the worlds' ecosystems, this increased demand for food and fiber is likely to be the deathblow for many of our natural treasures. If we are to preserve the quality of life on this planet, then the rapid development and implementation of technology that helps to protect the natural environmental is essential. One such technology produces building blocks from locally available soils or earth. Compressed Earth Block (CEB) and Stabilized Compressed Earth Block (SCEB) construction is a time proven, ecologically friendly building system. These blocks require very little energy input to produce unlike the processed materials utilized in concrete, wood frame, or steel construction methods. This makes CEB and SCEB about 70% cheaper to produce and utilize when compared to other construction methods. CEB or SCEB walls that are greater than 22″ thick also provide an excellent “thermal storage unit” for passive solar housing. Even without solar gain or insulation, this massive wall system is 70% more energy efficient to heat and cool than other construction technologies. Other advantages of CEB and SCEB construction include being fireproof, bug-proof, and hypoallergenic. In addition, when CEB and SCEB walls of over 22″ thick are properly constructed the resultant structure can be tornado, hurricane, and earthquake proof as well. And with new waterproofing systems CEB and SCEB can be constructed anywhere in the world, from the rainforests of the tropics to the high deserts. Thus a major improvement in CEB and SCEB production methods and utilization technology can provide shelter for billions of additional people while helping to conserve our precious natural resources.
2. Discussion of Prior Art
All current state of the art machines share a common feature. They utilize a completely enclosed mold or compression chamber usually with a hydraulic cylinder providing compression to the chamber to produce one block at a time. A few machines can vary one dimension of the block being produced by varying the length of the compression stroke. However, ultimate block size is always limited to the size of the mold or compression chamber of an individual machine. And since earth placed under compression exhibits what I call the “bridging effect”, this severely limits the ultimate block size that these machines can produce.
A simple explanation of the “bridging effect” is, as earth nearest the ram or applied force compresses it bonds together forming in effect, a “bridge”. This layer of dense material effectively transfers any additional applied energy or pressure outwardly (in a chamber—to the chambers walls) effectively shielding the underlying material from the applied pressure. The “bridging effect” thus limits the amount of earth that we can effectively compress or compact at one time. The same principle holds true for other earthen construction projects. Highway Engineers restrict maximum “lift” depth to 8″ of loose earth during roadbed construction. Experience has taught them that it is almost impossible to achieve a high-density (98% Standard Density) roadbed if you try to compact more than 8″ of loose earth in a single lift. The same holds true for CEB and SCEB production. Since loose earth shrinks by roughly 50% during the compaction process due to the removal of air, this leaves about 4″ of compacted road base. Thus we can conclude that after 4″ of compressed material accumulates then the “bridging effect” will start to severely affect compaction efficiency. And, although compacting earth within a chamber is more efficient than compacting earth in a roadbed, in a CEB machine, the maximum block size when measured through the dimension of applied pressure should never exceed 6″ (compacted thickness) or a significant loss of density will likely result. The only way to overcome this 6″ limitation is to apply extreme amounts of additional compaction pressure, which is entirely possible but not at all economical. This is the main reason present (state of the art) CEB machines restrict their production to small blocks, usually less than 4″ thick when measured through the dimension of applied force. This relegates them to producing blocks of less than 40 lbs and generally less than 20 lbs. Remember, all blocks presently produced are laid utilizing manual labor. Indeed, the focus of the prior art has always been tilted towards increasing the speed of production and not block size.
Unfortunately, this lack of block size restricts CEB and SCEB construction projects in developed nations, to mostly high-end custom projects due to the high manual labor costs involved. It has also limited the wall thickness of most CEB projects to less than 14″. While this is structurally acceptable, CEB and SCEB walls need to be at least 22″ thick to take full advantage of their thermal storage properties. Which means that most CEB and SCEB walls being built presently need to be insulated just like other building systems. Thus, due to the limitations imposed by present state of the art production technology, CEB and SCEB construction has not been utilized nor accepted by industrialized cultures as the energy efficient low cost building system that it should be.
If we are going to modernize the technology and make it more acceptable to industrial societies then human labor to lay the blocks must be replaced by mechanical equipment. This will require a CEB and SCEB machine capable of producing large blocks that can be efficiently handled and placed utilizing standard construction equipment. This will require CEB machines capable of producing blocks that are between 100 lbs. and 500 lbs. for economical placement by a standard sized backhoe. A large commercial project might require CEB blocks between 1 and 5 tons for economical placement utilizing large excavators, cranes, or other equipment common to this environment. Not only will this lower the cost of installation for CEB and SCEB construction, but these massive blocks fit perfectly into the thermal efficiency requirements for earthen construction.
Thus, all that can be said for the present (state of the art) machines is that they have improved the quality and speed of CEB and SCEB production. However, it is still necessary to utilize a 6,000 year-old technology to manually place the blocks within a building system. In this regard we have regressed as many ancient cultures were far more advanced in the utilization of earthen construction than we are. This allowed them to build great civilization centers containing hundreds of thousands of people while causing a minimum of damage to their natural environment. While we think of the ancient Egyptians, Incas, and Aztecs as great builders with rock, it was earthen housing of the masses that allowed their civilizations to flourish. Not that we need to copy the past, but we should be willing to combine the best of the past with the best of the present to produce what is best for the future.
My ramming invention has only one thing in common with a current (state of the art) machine. They are both capable of producing a compressed earth block. The means and method by which this is accomplished is however, totally different. Indeed, all I can list as prior art are examples of dissimilar design and method. This becomes readily apparent upon examination of the art.
3. Description of Prior Art
Underwood, U.S. Pat. No. 6,347,931 issued Feb. 3, 2000 describes an apparatus for forming building blocks, which features a fill chamber followed by a ramming (i.e., compression) chamber that is blocked by a headgate. The earthen block is compressed by a hydraulic ram pushing the material against the headgate then the headgate is opened to eject the block.
Kofahl U.S. Pat. No. 5,919,497 issued July 1999 describes an apparatus for forming building blocks. In operation, a soil/cement mixture is loaded into the upper end of the compression chamber, a sliding gate is slid shut, and a ram compresses the mixture against the gate.
Elkins U. S. Pat. No. 4,579,706 issued April 1986 describes an apparatus for making blocks from earth, soil, or like material. This patent utilizes two enclosed compression chambers and alternates between them to speed production.
As is readily apparent, all the above-mentioned patents utilize completely enclosed compression chambers to form a particular sized block.
An example of current (state of the art) machines on the market includes the “Impact 2001”, and the “Compressed Soil Block Machine” manufactured by Advanced Earthen Construction Technologies, Inc. of San Antonio, Tex. Other examples of CEB machines includes the “Terra-Block 250” manufactured by Terra-Block International, Inc. of Florida and the “HBP 250” manufactured by Vermeer Manufacturing, Inc. of Iowa.
All the above stated machines feature micro-processor controlled automated production cycles and high output capabilities, but they all produce blocks of such small size as to require manual labor to handle and lay the blocks within a building system. None of the above stated machines can feasibly be adapted to produce blocks of over 100 lbs. And none of the above stated machines can produce blocks with a variety of lengths without changing out the mold in the compression chamber.
Objects and Advantages
It is therefore an object of this invention to provide a compaction unit of simple design that can produce blocks of relatively high-density with very consistent height and width, and infinitely variable yet controllable length.
It is also an object of this invention to provide a compaction unit that utilizes the previously compacted material (lifts) as an integral part of the unit.
It is a further object of the invention to provide a compaction unit with a ramming head that by design and function increases the “frictional threshold” or resistance to movement of the material being compressed within the ramming chamber.
It is yet another object of this invention to provide a compaction unit that can produce blocks with interlocking features, or channels/chases for carrying wire, reinforcing steel, or piping.
It is another object of this invention to provide a relatively small machine that can produce blocks of sufficient size that they can be efficiently handled (individually) and placed within a building system by standard construction equipment.
It is yet a further object of this invention to provide a machine that can be used as a stationary manufacturing facility, or can be trailer mounted for easy transport to and around the job site.
It is still yet another object of this invention to provide a ramming machine that utilizes at least two compaction units driven by a single power source to increase the speed of production.
It is another object of this invention to provide a ramming machine that can be controlled manually, semi-automatically, or can be fully automated having a microprocessor with programmable production schedules and radio input capabilities.
It is still another object of this invention to describe a process whereby blocks produced by this ramming machine are efficiently placed (individually) within a building system utilizing standard construction equipment.